Common-Mode Emissions Measurements and Simulation in Variable-Speed Drive Systems

In order to efficiently reduce electromagnetic interference emissions, especially common-mode (CM)-conducted noise emissions, which are the most disturbing in any variable-speed drive systems, the understanding of behavior and the knowledge of propagation path of parasitic currents in the system are essential. In this paper, a simple CM disturbances modeling is proposed to predict or estimate the CM noise currents. The modeling principle is based on specific experimental characterizations and the modeling of the complete CM circuit considered as a chain of quadripolar matrices. Each part of the system is represented by a two-port network associated in cascade using matrix [T]. The comparison between calculations and experiments in a variable-speed drive system effectively confirms the validity of the proposed approach. Parametric studies carried out herein using this valid model will show the way in which CM currents could be reduced or eliminated in a considered existing system.